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Continuously cast shape memory and super elastic alloy wires produced by a new continuous casting route

采用新连铸工艺生产的连铸形状记忆超弹性合金丝

基本信息

批准号：
12555209
负责人：
MOTOYASU Genjiro
金额：
$ 6.14万
依托单位：
Chiba Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

项目摘要

The aim of this research is development of soft copper shape-memory, super-elastic alloy material in place of the usual hard Ti-Ni alloy. The copper alloy wire with high rubber elasticity has the possibility to become the useful spring part for the industrial materials.In this research, the possibility of applying the OCC process to the fabrication of Cu-Al-Ni and Cu-Sn shape memory, super-elastic alloy wires was investigated. It was established that shape memory wires 2 mm in diameter can be continuously cast by OCC process. Cast OCC wires were found to be of single crystal or unidirectional solidified structure with a matrix phase β_1 in which γ_2 particles were precipitated in the form dendrites along the sub-grain boundaries. The γ_2 particles became fewer and the size became finer with an increase in casting speed. The Ms transformation temperature for the Cu-Al-Ni alloy and Cu-Sn alloy was in the range -19℃ to 3℃ and -55℃ to -50℃, respectively, giving rise to super-elastic behavior at the room temperature. The wires cast at slower speeds displayed shape memory attributes on heating to 90℃, whereas the wires produced at higher casting speeds exhibited super elasticity at room temperature. The Cu-Al-Ni alloy wires produced at higher casting speeds exhibited two-step super-elastic transformations as a single crystal wires. In addition, the fatigue failure of the Cu-Al-Ni alloy wires occurred after 25000 bend cycles, which was 10 times that of the conventional Ti-Ni wires. Bending properties of the OCC Cu-Al-Ni alloy wires, such as the softness and the fatigue limit, were superior to those of the conventional Ti-Ni wires.These findings suggest that the OCC process could be useful for the production of super-elastic single crystal or unidirectional solidified Cu alloy wires.

本研究的目的是开发一种软质铜形状记忆超弹性合金材料，以取代通常的硬质钛镍合金。高弹性铜合金丝材具有成为工业用弹性材料的潜力，本研究探讨了将OCC工艺应用于Cu-Al-Ni和Cu-Sn形状记忆超弹性合金丝材的可能性。结果表明，采用OCC工艺可以连续铸造出直径为2mm的形状记忆合金丝。结果表明，铸态OCC丝材为单晶或单向凝固组织，基体相为β_1，γ_2以树枝晶形式沿亚晶界沿着析出。随着拉速的提高，γ_2颗粒数量减少，尺寸变细。Cu-Al-Ni合金和Cu-Sn合金的Ms转变温度分别为-19 ℃~3 ℃和-55 ℃~-50 ℃，在室温下表现出超弹性行为。以较慢速度铸造的丝在加热至90 ℃时显示形状记忆属性，而以较高铸造速度生产的丝在室温下显示超弹性。在较高拉速下制备的Cu-Al-Ni合金丝表现出单晶丝的两步超弹性相变。此外，Cu-Al-Ni合金丝在25000次弯曲循环后即发生疲劳失效，是传统Ti-Ni丝的10倍。OCC Cu-Al-Ni合金丝材的弯曲性能（如柔软度和疲劳极限）优于传统Ti-Ni合金丝材，表明OCC工艺可用于制备超弹性单晶或单向凝固Cu合金丝材。